The present invention relates to a process of administering to growing canines a pet food composition comprising appropriate amounts and ratios of n-6/n-3 fatty acids to enhance bone modeling and chondrocyte functioning in those animals.
It is known from Canadian Patent No. 2,145,716 that dietary n-6 and n-3 fatty acids (also known as omega-6 and omega-3 fatty acids) and the ratio in which they are present in the canine diet has an effect on the skin and coat health of the animal. Studies have demonstrated that the incorporation of optimal proportions of n-6 and n-3 fatty acids into the diet has a beneficial effect on canines suffering from certain inflammatory skin conditions.
Long bone growth and bone modeling are regulated by complex interactions between a puppy""s genetic potential, environmental influences, and nutrition. These interactions produce a bone architecture that balances functionally appropriate morphology with the skeleton""s role in calcium and phosphorous homeostasis. Long bones of the dog increase in length and diameter by a process called modeling. Bone modeling represents an adaptive process of generalized and continuous growth and reshaping of bone governed by the activities of osteoblasts and osteoclasts until the adult bone structure is attained. Bone modeling is distinct from bone remodeling which describes the process of bone resorption and formation that maintains skeletal mass in the adult dog.
There are numerous cell-derived growth regulatory factors present within skeletal tissues such as prostaglandins, cytokines, and growth factors which affect skeletal metabolism. Prostaglandins are believed to play a major role in bone metabolism, but also have been implicated in joint diseases. Some of the skeletal abnormalities and conditions in canines are the consequence of abnormal bone remodeling and metabolism, or in the case of arthritis, an inflammatory process.
Growth cartilage in long bones contains chondrocytes which initiate bone mineralization through matrix vesicles which have been described as lipid-enclosed microenvironments containing acidic phospholipids that exhibit a high affinity for binding calcium ions. Polyunsaturated fatty acids (PUFA) are believed to play an important role in bone mineralization and growth because it is believed that phospholipids as well as prostaglandins are synthesized from essential PUFA.
Recent studies have demonstrated that dietary n-6/n-3 fatty acids ratios are reflected in the fatty acid profile in the bones and growth cartilage of growing chicks and in the bones of rats. In these studies, chicks provided with soybean oil in their diet had greater values for ex vivo PGE2 (prostaglandin E2) production in liver and bone cultures, but lower bone formation rates as compared to chicks fed menhaden oil. The level of PGE2 produced locally at the bone appears to be a critical factor in bone formation in that it is stimulatory at moderate levels and inhibitory at high levels. The mechanism by which prostaglandins regulate bone metabolism is uncertain but it has been suggested that it may be mediated through the IGF system and(or) cytokines.
Accordingly, the need remains in the art for a diet which promotes bone/cartilage biology and health in the growing canine, which diet includes appropriate amounts of dietary n-6 and n-3 fatty acids.
The present invention meets that need by providing a process of administering to a growing canine a pet food composition comprising an appropriate amount and ratio of dietary n-6 and n-3 fatty acids to provide improved bone modeling and chondrocyte functioning. In accordance with one aspect of the present invention, a process is provided for improving bone modeling and chondrocyte functioning in a growing canine comprising the step of feeding the growing canine a pet food composition comprising n-6 and n-3 fatty acids in an amount and ratio effective to improve bone modeling and chondrocyte functioning. The ratio of n-6 fatty acids to n-3 fatty acids is preferably from about 20:1 to about 1:1, more preferably, from about 10:1 to about 5:1, and most preferably, from about 8:1 to about 5:1. It is preferred that at least about 22 wt% of the total fatty acids in the pet food composition are n-6 fatty acids. It is also preferred that at least about 3 wt% of the total fatty acids in the pet food composition are n-3 fatty acids.
Preferably, the pet food composition comprises from about 0.88 to about 6.6% by weight n-6 fatty acids and from about 0.16 to about 1.2% by weight n-3 fatty acids, on a dry matter basis. Thus, both the amount of n-3 fatty acids in the pet food composition, as well as the ratio of n-6 to n-3 fatty acids, are important. In a preferred embodiment, the n-3 fatty acids provided in the pet food composition comprise eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Preferably, the pet food composition comprises from about 20 to about 40 wt% crude protein, from about 4 to about 30 wt% fat, from about 2 to about 20 wt% total dietary fiber, and a source of carbohydrates. No specific ratios or percentages of these nutrients are required.
The pet food composition may further comprise from about 1 to about 11 weight percent of supplemental total dietary fiber of fermentable fibers which have an organic matter disappearance of 15 to 60 weight percent when fermented by fecal bacteria for a 24 hour period.
Accordingly, it is a feature of the present invention to provide a process for improving bone modeling and chondrocyte functioning in a growing canine. This, and other features and advantages of the present invention will become apparent from the following detailed description and the appended claims.